1. Field of the Invention
The invention relates to novel terpene derived sulfonates, their use as hydrotropes and processes for their preparation.
2. The Prior Art
Many aqueous compositions contain organic components of poor water solubility. Hydrotropes are formulated into these liquids to increase the aqueous solubility of the hydrophobic organic components. Commonly employed hydrotropes include the salts of toluene, xylene or cumene sulfonates. While these commercial compounds perform satisfactorily, there is a need for lower cost alternatives, especially materials not derived from petrochemical feedstocks.
Among the relatively low-cost renewable raw materials is turpentine, an extract of pine trees. Major components of turpentine are .alpha.- and .beta.-pinenes. When reacted with pyrosulphuryl chloride, .alpha. and .beta.-pinenes yield sulfonate compounds as in U.S. Pat. No. 2,220,678. Traynor et al, J. Org. Chem., Vol. 44, 1557, 1979, reports that sodium p-menth-6-ene-2-sulfonate can be formed from the dehydration of the reaction product between sodium sulfite and the .alpha.-pinene derivative limonene oxide. This publication further discloses that .beta.-pinene will react with sodium bisulfite to form sodium p-menth-1-ene-7-sulfonate. Little has been reported concerning the utility of these sulfonated pinene derivatives. U.S. Pat. Nos. 4,224,240 and 4,283,347, however, mention the possibility utility of p-menth-1-ene-7-sulfonate salts as detergents and surfactants.
Reaction of .beta.-pinene with formaldehyde forms the very useful intermediate 6,6-dimethyl-bicyclo[3.1.1]hept-2-ene-2-ethanol, commonly referred to as Nopol. Little is known of sulfonated Nopol derivatives.
Accordingly, it is an object of this invention to describe novel sulfonated Nopol derivatives.
Furthermore, it is an object of this invention to provide processes for the manufacture of certain sulfonated Nopol derivatives.
Another object of this invention is to provide a method for solubilizing only partially water-soluble compounds in aqueous formulations by means of Nopol derived sulfonate hydrotropes.